Biology and morphometric relationship of gall inducers Contarinia sp. and corresponding parasitoids for swollen galls of Nitraria sibirica pall

Galls function as provide shelter for gall inducers, guarding them against their natural enemies. Previous research has illuminated the interactions between galls, gall inducers, and their corresponding parasitoids within various caltrop plants. However, less is known about these relationships within Nitraria sibirica, particularly regarding the efficacy of parasitism. Therefore, this study aimed to identify the morphometric relationships among the swollen galls, gall inducers, and their parasitoids. Two species of gall inducers and three species of parasitoids were obtained from the swollen galls of N. sibirica. The correlations of the parasitization indexes, the lifespan of gall inhabitants, and temperature and the morphometric relationships between the galls and their inhabitants were analyzed. The dominant gall inducer identified was Contarinia sp. (Diptera: Cecidomyiidae). Furthermore, it was observed that three solitary parasitoids attacked Contarinia sp. in the swollen galls, with only Eupelmus gelechiphagus acting as an idiobiont ectoparasitoid. The dominant parasitoids were Platygaster sp. and Cheiloneurus elegans at sites 1 and 2, respectively, with Platygaster sp. displaying greater abundance than C. elegans in the swollen galls. The lifespan of the gall inhabitants shortened gradually as the temperature increased. Moreover, the optimal number of gall chambers ranged from two to four per swollen gall with maximized fitness, which can be considered the optimal population density for the gall inducer Contarinia sp. Morphometric analysis exhibited a strong linear correlation between gall size and chamber number or the number of gall inhabitants, as well as a weak correlation between gall size and body size of the primary inhabitants of swollen galls. Our results highlight the importance of the biological investigation of parasitoids and gall inducers living in closed galls with multiple chambers and may pave the way for potential application in biological control.

Integrative Taxonomy of Nitraria (Nitrariaceae), Description of the New Enigmatic Species and Key to All Currently Known Species

A new species, Nitraria iliensis sp. nov., is described from the Ili basin, Almaty region, Kazakhstan. It belongs to section Nitraria ser. Sibiricae and is morphologically similar to N. sibirica Pall. An integrative taxonomic approach based on molecular, biochemical and morphological analyses, along with palynological data, was used to delimit this new species. The studied species of the genus are illustrated, and photographs of authentic specimens of the new species, as well as a distribution map of the new species and segregate taxa, are provided. Morphological characters were investigated, more important traits for identification were found, and a new key to distinguish between all species of the genus was prepared.

Pollen Morphology of Some Species from Genus Nitraria

An analysis of pollen grains (in Nitraria sibirica Pall., N. schoberi L., N. komarovii Iljin & Lava ex Bobrov, and N. pamirica L. Vassil.) was performed on natural material collected in Russia, Kazakhstan, and Tajikistan. Herbarium specimens from the collection at Komarov Botanical Institute, Russian Academy of Sciences (N. tangutorum Bobrov and N. praevisa Bobrov) were examined, too. Pollen grains of two species-N. pamirica and N. praevisa-were studied for the first time. N. tangutorum and N. praevisa were found to have the perprolate pollen shape, whereas N. pamirica was found to have the subprolate shape. An intraspecific differentiation of N. sibirica was noted. Populations of N. sibirica (Taskarasu, Karatal, and Basshi) possess pollen grains of the subprolate or prolate shape, striate and perforate exine ornamentation, and a longer equatorial axis and a shorter polar axis than other specimens of N. sibirica. N. schoberi in all populations had anomalous shapes of some pollen grains. Overall, we demonstrated that the length ratio of the polar axis to the equatorial axis, characteristics of pollen in polar view, colpus morphology, and surface ornamentation of pollen grains in the genus Nitraria are of great taxonomic importance for the identification of species.

Morphological Variability of Nitraria Species in Central and Southern Kazakhstan

Abstract

The variability of metric traits has been studied in 20 Kazakhstan populations of three Nitraria species (N. schoberi L., N. sibirica Pall., and N. komarovii Iljin & Lava ex Bobrov). According to the results, N. sibirica differs from N. schoberi and N. komarovii in small leaves, fruits, and seeds, as well as in the structural features of inflorescences and flowers. N. sibirica is characterized by a greater number of flowers per inflorescence (25–66 on average) than N. schoberi and N. komarovii (14–28 on average). Additionally, N. sibirica differs from N. schoberi by narrower (1.3×) petals and smaller anthers (1.46× in length and 1.2× in width) and pistils (1.25× in length and 1.44× in width). N. komarovii differs from N. schoberi by narrower leaves (1.7×). N. komarovii is characterized by relatively large (especially in width) size of anthers that, together with smaller petals, makes it possible to distinguish this species during flowering. Flowers of N. komarovii are bright yellow, while those in N. schoberi and N. sibirica are white and light purple, respectively. N. komarovii fruits are orange, pale red, or bright red. Fruits of N. schoberi and N. sibirica are dark burgundy and black, respectively. At the intraspecific level, most of the studied metric traits (except for the habitus of N. sibirica plants) are stable and do not depend on the 16 climatic parameters of plant habitats. At the same time, a number of morphological features have been revealed in N. sibirica plants from the Ili Depression. In these populations, N. sibirica plants form shrubs up to 1.8 m in height with a large (up to 90) number of flowers per inflorescence, large petals (3.5 mm in length and 2.2 mm in width on average), small (~0.6 mm) anthers, small (5–5.5 mm in length) fruits, and small (~4 mm in length) narrow ovate stones. These features indicate the ecological–geographical differentiation of N. sibirica under the extra-arid conditions of the stony desert of the depression and evidence a separate taxonomic rank of these populations.